1. Field of the Invention
The present invention relates to a gas burner for use in a furnace and a method of burning gas in a furnace, especially but not exclusively a process furnace used in an oil cracking or refining process.
2. Summary of the Prior Art
Generally such furnaces will have a single burner or an array of burners arranged on the furnace floor, each burner being supplied with a fuel gas which it burns in order to heat the furnace.
For environmental reasons it is desirable to keep the level of NOx emissions from the furnace as low as possible. It is known that NOx emissions from a burner can be reduced by recirculating flue gas (the gaseous products of combustion in the furnace) and mixing it with air in a windbox (located below the floor of the furnace) which supplies the combustion air flow to the burner. However, this requires large amounts of recirculated flue gas (RFG) and a large amount of energy to pump the recirculated flue gas into the windbox. There is a need for a more efficient way of reducing NOx emissions from a gas burner.